Research of the BWS system for lower extremity rehabilitation robot.

Body weight support (BWS) system is increasingly used in conjunction with treadmills to assist the patients with neurological impairments. Owing to lower limbs of the patients unable to bear the whole weight during the rehabilitation training, some weight can be removed to help the patients recover the basic walking ability gradually. Therefore, considering the man-machine relationship and the effects of the rehabilitation, a wire-driven BWS system is designed. The main unit of the system is an active closed-loop controlled drive to generate the exact desired force. The force acted on the body is through the adjustment of the length of the rope which is connected to the harness worn by the patient. The structure designed in the research is easy to operate to realize the goal of the rehabilitation. To verify the effectiveness and practicability of the BWS system, some experiments have been curried out. From the results, not only the constant unloading force can be realized, but also the response time is limited in a small range which can bring a positive effect on correcting gait, improving balance and reducing muscle spasms. Also, compared to the traditional body weight support system, such as static system or passive elastic system, it has the advantages of the fast response, small errors and constant unloading force.